Pulp roller for a papermaking machine



Feb. 2l, 1967 P. slEGEL.

PULP ROLLER FOR A PAPERMAKING MACHINE Filed July l5, 1964 www nz n.4.

/N VL'N' 0F PETER' .515651.

United States ate'nt many Fired Jury 15, 1964, ser. No. 382,790 s Craims.y (ci. 162-314) This invention relates to dandy rollers or pulp rollers, and more specifically to a pulp roller of the type used in paper manufacturing machines yfor cooperation with draining devices such as -circular or elongated filter sections or cell filters during processing a fresh web of paper pulp.

These known draining devices feed a fresh Web of paper pulp to the pulp roller and then convey it into the paper manufacturing machine. ln .the following it is assumed, for example, that in a known arrangement a cell filter is provided for cooperation with the pulp roller.

A cell filter consists of a hollow cylinder which by its horizontal axle is arranged for rotation in bearings on the upper rim of a container. The jacket of the cylinder is made of perforate sheet metal, with a felt-cov ered narrow-mesh wire cloth of metal running thereover. The interior of the cylinder is subdivided into sector-shaped cells by means of radial walls. Within these cells there prevails a permanent vacuum. The lower portion of the cylinder dips into a watery paper pulp solution in the container. Owning to the vacuum in the cells, the dipping portion of the cylinder periphery constantly sucks paper pulp solution onto its surface, i.e. the water is sucked into the cells from where it is drained, while the paper pulp is retained on the periphery of the cell filter cylinder, i.e. on the felt covering thereof. During rotation of the cell filter, the periphery of its cylinder feeds the web of paper pulp from the container upwardly toward the pulp roller which serves for further processing the web of paper pulp which at this stage still is'a loose, thick and uneven web containing water.

As is known, such pulp rollers likewise are rotatable about a horizontal axle and also consist of a hollow cylinder having a perforate felt-covered jacket. Within the pulp roller, a plurality of sheet metal plates delining drain channels are arranged, each of which by its outer longitudinal edge is tangentially secured to the inner circumference of the jacket and by its inner longitudinal edge to the axle of the pulp roller, in such a manner that the channels are turned in the direction of rotation of the pulp roller. Any two consecutive sheet metal plates form a channel which continuously nar rows in width toward the axle. In one of the end walls of the pulp roller there is an aperture through which the water can be drained. The jacket of the pulp roller engages that part of the cell filter jacket, i.e of the web of paper pulp thereon, which on the ascending side of the circumference is about 45 degrees above the horizontal plane. The pulp roller is movable transversely of its central axis so that its jacket can be approached to the jacket of the cell filter to a greater or lesser degree and thus a corresponding pressure on the web of paper pulp exerted. The pulp roller is driven so that its periphery moves at the same speed as .the periphery of the cell filter. The pulp roller is to press water out of the web of paper pulp ascending on the -cell filter pe* riphery and to Hatten, compress and reduce the thickness of the web of paper pulp. During this operation, the water pressed out of the paper pulp by the pulp roller is forced through the perforate jacket thereof and received by the drain channels. By the rotation of the pulp roller, .the drain channels are inclined and the water is poured in the direction of the pulp roller axis and then led to the drain end for discharge.

In these known pulp rollers, only a limited number of sheet metal plates can be accommodated owing to restricted space and other constructional reasons. In an arrangement using, for example, six sheet metal plates, the outer longitudinal edges thereof are spaced apart from one another on the inner wall of the pulp roller jacket by a distance corresponding to one sixth of the circumference of the jacket. Within these large circumferential portions of the pulp roller jacket there is no direct possibility of enabling the water entering through the jacket to be conducted inwardly. Rather, the water will get out again through the perforate jacket and the cloth covering thereof and pour down onto the web of paper pulp ascending on the cell filter jacket. Thereby, paper pulp is washed off the web and back into the container, i.e. the web of paper pulp is damaged. The quantities of paper pulp thus washed away must again be sucked onto the cell filter. This mode of operation involves unproductive material circulation and a reduced output.

To eliminate these drawbacks, the present invention provides a pulp roller of the specified type which comprises a cylindrical perforate jacket defining a hollow cylinder and having circular end walls, a hollow shaft extending concentrically through said hollow cylinder and said circular end walls, a plurality of trough-shaped sheet metal plates defining drain channels between them and arranged within said hollow cylinder and each having an outer and an inner longitudinal edge, said outer longitudinal edges of said sheet metal plates being secured in uniformly spaced relationship and at an acute angle to the inner wall of said cylindrical perforate jacket, and a plurality of baffles disposed in the intervals between said spaced apart outer longitudinal edges at the same acute angle as said sheet metal plates and in Venetian blind fashion in relation thereto and to one another.

These lbaffles are intended to prevent the water entering the pulp roller between the outer longitudinal edges of the sheet metal plates from leaving it again through the jacket in that such water will be constantly supplied to the following drain channel by way of the inside of the bafiies. Consequently, the water is also prevented from pouring down onto the web of paper pulp ascending from the cell filter circumference so Vthat damage to the web of paper pulp is avoided, unproductive circulation of material is eliminated and paper output is increased.

A further shortcoming of the known pulp rollers consists in that the sheet metal plates are too small and secured by their inner longitudinal edges to the axle of the pulp roller. Due to their insufficient width, the sheet metal drain channels sweep `through too small an angle of the pulp roller and fail to penetrate deep enough therein. When tipping the drain channels downwardly over the pulp roller axle, water still present in the drain channels can pour onto and through the jacket and thus also cause damage tothe web of paper pulp. In a known pulp roller, this shortcoming is intended to be eliminated by arranging a baiiie plate on the rear side of each sheet metal plate to extend at right angles therefrom. These baflie plates are to retain residual water on the bottom of the drain chan nels. However, this is only achieved during slow rotation of the pulp roller, which, as a matter of course, reduces the output. During fast rotation of the pulp roller, the residual water ows over the bafiie plates and from the depth of the drain channels powerfully pours down onto and through the perforate jacket and on the web of paper pulp, causing relatively serious damage thereto.

To effectively eliminate the aforementioned shortcoming, the present invention proposes that the sheet metal plates have a width such as to extend from their outer longitudinal edges to their inner longitudinal edges through an angle of 240 Idegrees into the hollow cylinder.

Due to the enlarged width of the sheet metal plates extending through lan increased angle of the pulp roller, the water received by the drain channels can be conducted correspondingly deeper into the pulp roller so that it is prevented Ifrom pouring out of the channels because when the channel bottom is tipped downwardly, the outer portions of the drain channels are once again directed upwardly so that the residual water cannot pour down. Moreover, the inner longitudinal edges of the drain channels 4may be spaced apart from the periphery of the hollow shaft so that a slot-shaped passage is defined between the said inner longitudinal edges `and the said periphery, through which passage any residual water is permitted to flow from one drain channel into the following one and thus is prevented from passing out through the perforate jacket of the pulp roller. This design and arrangement of the drain channels also enables the pulp roller and the cell filter and consequently also the paper machine to be operated at a higher speed, which results in an increased output.

The known sheet metal plates have the disadvantage that they have a circular larc profile. Owing to this configuration, the centers of gravity of the water contained in the different drain channels are located at different and relatively large distances from the central axis of the pulp roller. Therefore, considerable torques are required for rotating the pulp roller which during rotation has to move and lift the water in the drain channels together with the same. The different location of the centers of gravity of the water in the individual drain channels also results in an unbalanced load application to the pulp roller which may cause the latter to vibrate. Due to such vibrations again, a constantly changing pressure would be exerted on the web of paper pulp so that this could not be evenly and smoothly manufactured. The vibrations of the pulp roller also might be transmitted to the cell filter and cause the web of paper pulp to slide off its circumference.

To eliminate this disadvantage, it is also proposed by the present invention that the sheet metals conveniently have an involute cross section.

Due to this configuration of the sheet metals, the centers of ygravity of the water contained in the individual drain channels are located on a common vertical which touches the center circle of the involutes and thus is very close to the central axis of the pulp roller. In this arrangement, the quantities of water act with a correspondingly small lever arm (radius) on the pulp roller so that the pulp roller needs but correspondingly low torques for moving the quantities of water. Due to the balance of the centers of gravity of the quantities of water, vibrating of the pulp roller is eliminated and consequently also the disadvantages resulting therefrom.

If the yaforedescribed features are appropriately combined, an extremely efficient pulp roller will be obtained.

An embodiment of the invention will now be described by way of example land with reference to the accompanying drawing, in which:

FIG. 1 is a cross section through a pulp roller according to the invention;

FIG. 2 is an axial section through part of the pulp roller, and

FIG. 3 is a cross-sectional view, on an enlarged scale, of part of the periphery of the pulp roller.

With reference now to FIGS. 1 to 3 of the drawing, the pulp roller proposed by the present invention is in the form of a hollow cylinder having a perforated jacket 1 covered with felt 2 and closed at both ends by end Walls 3. Over its longitudinal extension, the hollow cylinder 5 is subdivided by partition walls 4. The end walls 3 and the partition walls 4 are provided with apertures 9. With central bores in the end walls 3 and the partition walls 4, the hollow cylinder 5 is seated on a hollow shaft 6 in either end portion of which a short axle 7 is titted. By portions of the short axles 7 projecting outwardly of the cylinder 5, the pulp roller is rotatably mounted in a device, not shown, which, for example, may consist of pivotally mounted levers by means of which the pulp roller would be movable and adjustable transversely of its central axis, thereby to move the pulp roller with its periphery to a greater or lesser degree toward the periphery of a cell filter in order to determine the pressure exerted on a web of paper pulp 15 and thus the thickness thereof. One or both axles 7 -of the pulp roller are positively connected with a rotary drive, not shown.

Within the hollow cylinder 5, a number of, for example six, sheet metal plates 8 forming drain channels between them are arranged and provided with outer longitudinal edges 8' along which they are secured at an acute angle to the inner wall of the jacket 1. The outer ends of the drain channels are directed into the direction of rotation of the pulp roller as indicated by arrow A in FIG. 1. When the pulp roller is rotated, the inclination of the drain channels will change. Water which is pressed out of -a web of paper pulp by the pressure exerted on the web by the felt covered jacket 1 and which thus gets within the hollow cylinder 5 through the perforated jacket 1 will be led by the drain channels toward the interior of the pulp roller from where it will be fed through the Vapertures 9 in the partition walls 4 and end walls 3 as well as through an outwardly attached sheet metal collar 10 into a funnel 11 `and further into a discharge pipe 12.

Between the outer longitudinal edges 8 of the drain channels, baflles 13 are arranged in Venetian blind fashion and extend at an acute angle from the inner circumference of the hallow cylinder 5 in the same manner as the sheet metal plates 8. The water which, after the -outer longitudinal edge 8' of one of the sheet metal plates 8 has passed a point 14 at which the pulp roller is forced against the web of paper pulp 15, has entered the pulp roller through the perforate jacket 1 is passed from one to the next baffle 13 and finally to the following drain channel. In this manner, Water is prevented from pouring from the pulp roller onto the web of paper pulp 15 fed upwardly toward the pulp roller by the periphery of the;A cell filter, so that the down-pouring water cannot damage the web of paper pulp 15. In this arrangement, the leading and trailing edges of the baffles 13 may overlap each other.

Each of the drain plates 8 is of such a width that from the outer longitudinal edge 8' to the inner longitudinal edge 8" thereof it extends about through 240 degrees into the pulp roller. This measure ensures that water 4taken up by the drain plates 8 is led far enough toward the hollow shaft 6. The inner longitudinal edges 8" are spaced apart from the periphery of the hollow shaft 6 so as to define therebetween a slot-like passage 16 for residual water, if any, which from an upper drain plate 8 can pour down onto a lower following one through the passage 16.

The drain plates 8 have an involute cross section, the centers for forming the involute being located on a circle 17 drawn closely around the circumference of the hollow shaft 6. By this design of the drain plates 8 it is obtained that the quantities of water contained in the channels are intersected at 18, which designates the centers of gravity of the cross sections of such quantities of water, by ya common vertical 19 touching the circle 17. The weight of the quantities of water therefore acts on the hollow shaft 6 and on the axles 7 of the pulp roller with a relatively small lever arm corresponding to the radius o'f the circle 17 so that correspondingly small torques are required at the axles 7 for moving the quantities of water.

n.9 Owing to the fact that the centers of gravity 18 of the quantities of water are uniformly located on the same vertical, vibrating 0f the pulp roller and the known detrimental effects caused thereby to the web ofpaper pulp `are reliably prevented.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in `all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning land range of equivalency of the claims are therefore intended to be embraced therein.

I claim:

1. A pulp roller of the type used in paper manufact-uring machines for cooperation with draining devices such as circular or elongated lter sections or cell lters, comprising a cylindrical perforate jacket dening a hollow cylinder and having circular end walls, a hollow shaft extending concentrically through said hollow cylinder and said circular end walls, a plurality of trough-shaped sheet metal plates defining drain channels between them and arranged within said hollow cylinder and each having an outer and an inner longitudinal edge, said outer 1ongitudinal edges of said sheet metal plates being secured in uniformly spaced relationship and at an acute angle to the inner wall o-f said cylindrical perforate jacket, and a plurality of baflles disposed in the intervals between said spaced apart outer longitudinal edges at the same acute angle as said sheet metal plates and in Venetian blind fashion in relation thereto and to one another.

2. A pulp roller as claimed in claim 1, wherein the bafcs overlap each other.

3. A pulp roller as claimed in claim 1, wherein the sheet metal plates have a width such as to extend from their outer longitudinal edges through an angle of 240 degrees into the hollow cylinder.

4. A pulp roller as claimed in claim 1, wherein the inner longitudinal edges of the sheet metal plates are spaced apart from the periphery of the hollow shaft so that a slot-shaped passage is defined therebetween.

5. A pulp roller as claimed in claim 1, wherein the sheet metal plates are of involute cross section, the centers for forming the involute being located on a circle surrounding the hollow shaft at a relatively close distance therefrom.

References Cited by the Examiner UNITED STATES PATENTS 1,147,331 7/1915 McCorkindale 162.*314 X 1,205,672 11/1916 Seybold 162-368 X FOREIGN PATENTS 106,059 12/1874 France. 180,835 1/1887 France. 260,875 6/1913 Germany. 1,123,902 2/ 1962 Germany.

DONALL H. SYLVESTER, Primary Examiner. I. H. NEWSOME, Assistant Examiner. 

1. A PULP ROLLER OF THE TYPE USED IN PAPER MANUFACTURING MACHINES FOR COOPERATION WITH DRAINING DEVICES SUCH AS CIRCULAR OR ELONGATED FILTER SECTIONS OR CELL FILTERS, COMPRISING A CYLINDRICAL PERFORATE JACKET DEFINING A HOLLOW CYLINDER AND HAVING CIRCULAR END WALLS, A HOLLOW SHAFT EXTENDING CONCENTRICALLY THROUGH SAID HOLLOW CYLINDER AND SAID CIRCULAR END WALLS, A PLURALITY OF TROUGH-SHAPED SHEET METAL PLATES DEFINING DRAIN CHANNELS BETWEEN THEM AND ARRANGED WITHIN SAID HOLLOW CYLINDER AND EACH HAVING AN OUTER AND AN INNER LONGITUDINAL EDGE, SAID OUTER LONGITUDINAL EDGES OF SAID SHEET METAL PLATES BEING SECURED IN UNIFORMLY SPACED RELATIONSHIP AND AT AN ACUTE ANGLE TO THE INNER WALL OF SAID CYLINDRICAL PERFORATE JACKET, AND A PLURALITY OF BAFFLES DISPOSED IN THE INTERVALS BETWEEN SAID SPACED APART OUTER LONGITUDINAL EDGES AT THE SAME ACUTE ANGLE AS SAID SHEET METAL PLATES AND IN VENETIAN BLIND FASHION IN RELATION THERETO AND TO ONE ANOTHER. 